Vein thrombosis is a medical condition wherein a blood clot, or thrombus, has formed inside a vein. Such a clot often develops in the calves, legs, or lower abdomen, but can also affect other veins in the body. The clot may partially or completely block blood flow, and may break off and travel through the bloodstream. Commonly, the clot is caused by a pooling of blood in the vein, often when an individual is bed-ridden for an abnormally long duration of time, for example, when resting following surgery or suffering from a debilitating illness, such as a heart attack or traumatic injury. However, there are many other situations that cause the formation of a blood clot.
Vein thrombosis is a serious problem because of the danger that the clot may break off and travel through the bloodstream to the lungs, causing a pulmonary embolism. A pulmonary embolism is an obstruction of the pulmonary artery or one of its branches by a blood clot or other foreign substance. A pulmonary embolism can be caused by a blood clot which migrated into the pulmonary artery or one of its branches.
This is similar to a blockage of the blood supply to the lungs that causes severe hypoxia and cardiac failure, and frequently results in death. For many patients, anti-coagulant drug therapies may be sufficient to dissipate the clots. For example, patients may be treated with anticoagulants such as heparin and with thrombolytic agents such as streptokinase.
Unfortunately, some patients may not respond to such drug therapy or may not tolerate such therapy. Also, there may be other reasons why an anticoagulant is not desirable. For example, patients may have an acute sensitivity to heparin or may suffer from prolonged internal and/or external bleeding as a result of such drug therapies. Also, such drug therapies simply may be ineffective in preventing recurrent pulmonary emboli. In such circumstances, surgical procedures are required to prevent pulmonary emboli. Methods for prevention of primary or recurrent pulmonary emboli when anticoagulation therapies are ineffective are well-defined in the prior art. The current standard of therapy for prevention of pulmonary emboli in patients who are classified high-risk or are unable to be anticoagulated is percutaneous insertion and placement of an inferior vena cava filter device.
Vena cava filters are devices which are implanted in the inferior vena cava, providing a mechanical barrier to undesirable particulates. The filters may be used to filter peripheral venous blood clots and other particulates, which if remaining in the blood stream can migrate into the pulmonary artery or one of its branches and cause harm.
Vena cava filters can filter the blood stream by catching and collecting particulates within the blood stream. However, the basket-like shape of the filter may cause the particulates to congregate or collect near the center of the blood stream. This can result in an occlusion within the inferior vena cava, particularly as the amount of particulates builds within the vena cava filter. Not only can this reduce the usable lifespan of the filter, but it can also potentially cause serious harm to the patient.
Therefore, an implantable lumen filter with an enhanced durability and methods for filtering a body lumen may be useful.
It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of example configurations of the present invention.